What Does A Blower Motor Relay Do? Symptoms and how to replace broken fan motor relay new for 2022

A blower motor relay is a vital component of your car’s cooling system. It helps to control the flow of air to your car’s radiator and fan. If your blower motor relay is not working properly, your car’s cooling system could be in trouble.

This amortips.com post will answer your question about “What Does A Blower Motor Relay Do?” and provide relevant information.

What Does A Blower Motor Relay Do?
What Does A Blower Motor Relay Do?


What Does A Blower Motor Relay Do?

What Does A Blower Motor Relay Do?
What Does A Blower Motor Relay Do?

To activate the HVAC system, the thermostat sets a temperature threshold. When the room’s temperature falls below that point, sensors in the thermostat send a signal to turn on the furnace.

The blower motor then pulls the warm air out of the furnace and powers a fan that pushes heated air out through vents and into the structure.

There are two main types of blower motors.

  1. Single-speed units have an on/off switch that operates at a consistent speed until the desired temperature is achieved.
  2. A multi-speed model allows you to adjust the fan speed, which can help to alleviate cold spots and make other temperature adjustments. This is more energy efficient, as it can control smaller temperature shifts.

How to Identify a Failing Blower Motor Relay

How to Identify a Failing Blower Motor Relay
How to Identify a Failing Blower Motor Relay

In a blower motor, the relay supplies power that allows fans to circulate warm air. The relay’s reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.

Blower motor relays often wear out over time from the stress of constantly switching back and forth.

The relay may be failing, which could result in the blower not working.

Blower motor does not function

One of the first indications of a problem with the blower motor relay is when the fan does not work at all. If this relay is defective, then power will be cut off to the blower motor circuit, causing it to stop working or not produce any wind from the vents.

Blown fuses

If the AC blower motor relay is experiencing any sort of problem, it may cause the blower motor fuse to blow. This would disable the relay and prevent it from distributing power properly across all electrical components in the system.

Melted relay

If you experience problems with your blower motor relay, one possible symptom is that it gets hot and starts to melt. This can lead to damage to the fuse box or panel, if not dealt with quickly.

If the blower motor relay fails, power to the blower motor will be lost and the AC system will be unable to distribute its cooled or heated air.

If you think your car’s blower motor relay is malfunctioning, have it checked out by a professional technician at YourMechanic. They can tell if the car needs a new relay or another repair to get the AC working properly again.

Steps to Replace a Motor Blower Relay

Steps to Replace a Motor Blower Relay
Steps to Replace a Motor Blower Relay

Follow these four steps to successfully restore motor blower functions:

Review the owner’s manual

If you are having trouble using your device, follow the troubleshooting steps included in the guide. These steps may help you to determine what is causing the issue and how to fix it.

If the fan does not produce any air movement or if there are no instructions, it is advisable to evaluate the fan’s functionality.

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The device appears to be functioning properly, but you may want to check the fuse panel for loose, missing, or damaged components and replace as needed.

Disconnect the motor from the main power supply.

To locate and replace a relay in a motor, follow the schematics included with your owner’s manual. Allen wrenches, a deep-socket set, a small flashlight, and some screwdrivers might be needed to get inside the motor.

The connector itself can be a small black box with wires of various colors running from both ends.

Once you’ve located the switch, carefully disconnect the damaged relay

Relays are often secured in place by plastic connectors. To disengage these mechanisms, apply pressure to them without damaging them.

Install the replacement switch and test it to ensure a proper connection.

If replacing the switch doesn’t resolve the issue, replace the blower motor relay

If your car has an AC or cooling fan, look for a relay with those terms listed on the schematics. If your car doesn’t have either of those, look for any relay that controls your blower motor.

Blower Motor Relays and Delay-on-Break Timers at Amperite

Blower Motor Relays and Delay-on-Break Timers at Amperite
Blower Motor Relays and Delay-on-Break Timers at Amperite

If a problem with your HVAC system is suspected, a quick replacement of the blower motor relay can quickly rectify the issue.

With Amperite’s time delay relays, you can ensure that your blower motor operates at its peak performance. Additionally, our delay-on-make components can help increase the efficiency and functionality of your climate control equipment.

Air Conditioning System

If the thermostat is set to delay-on-break, a normally closed delay-on-break TDR can be used to hold the blower motor in operation for a specified time after the cooling compressor has been turned off by the thermostat.

This allows the residual cooling effect in the evaporator coil to be used to provide extra BTUs of cooling after the compressor has stopped.

Blower Motors

A delay-on-make timer can be used to operate a blower motor which is to be delayed for a set amount of time after an electric, gas, or oil heater has been started.

To prevent the transfer of cold air into a room occupied by people, it is important to seal off any openings that allow cold air in.

F.A.Q about “What Does A Blower Motor Relay Do?”

How do I know if my blower motor relay is bad?

If your fan isn’t working due to a bad blower motor resistor, you won’t be able to get any airflow from the vents.

What happens if blower motor relay goes bad?

If the blower motor relay fails, it can cause the fuse to blow, cutting power to the fan.

What causes blower motor relay failure?

Blower motors tend to fail due to corrosion or overheating. If the resistance of the motor’s rotational gear causes an electric current that is too high, this can overheat and damage the blower motor resistor.

Why does my blower motor kick on and off?

Your furnace may be turning on and off when the furnace isn’t heating because of a defective fan limit switch.

Why does my blower motor resistor keeps melting?

Blower motor resistors can be shortened or even destroyed by drawing too many amps from the motor. This can be caused by faulty wiring, melted wires or plugs, and/or overheating of the resistor.

Why has my blower stopped working?

In the event that the motor on a system doesn’t work at any speed, one of three possible issues may be to blame: a blown power supply fuse, bad motor ground connection, or a failed motor. Blower motors are generally less likely to be affected than other types of motors.

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If the system does not operate with the blower turned off and no obstructions are in the way, it is most likely that either a blown fuse or an issue with one of the other components is responsible.

Where is blower motor relay located?

The blower relay is located near the front of the fuse block and is labeled “Blower.” If you notice that the metal rod inside is broken, then the relay will need to be replaced.

What does a relay switch do in a furnace?

The electric relay in a furnace is responsible for relaying electrical power to the heating elements and the blower motor inside the furnace cabinet. The heating elements provide heat to warm the air, and the blower motor sends this warmed air through ductwork.

Why does my blower motor not work on high?

If the blower is not working on high speed, check for a bad fuse or bad relay. If the relay is defective, replace it with another one that has the same part number. Finally, make sure there is a good ground connection to the relay

What causes a relay to fail?

A relay’s life is largely determined by the health of its contacts. Issues with high current in-rush, sustained currents, and voltage spikes can cause a relay to fail.

How can you tell if a relay fuse is blown?

If you are experiencing any of the following symptoms with your vehicle, it may be time to replace your starter relay fuse: problems starting the vehicle, the starter staying on after cranking the engine, and a clicking noise coming from the starter.

What would cause a furnace to not kick on?

If your furnace is not kicking on, it could be due to a problem with the thermostat. Make sure that the thermostat is switched to the heating function and then check to see if there are any obstructions in the furnace’s air flow. If there are no obstructions, then you may have an internal problem with your furnace that needs professional repair.

Can you bypass a blower resistor?

In the highest speed state, the blower resistor is bypassed and the fan is directly connected to the car’s battery. This allows maximum current through the motor.

Will a blower motor work without the resistor?

If the resistor shorts or fails, it may cause the blower motor to remain stuck on one speed. This would result in reduced functionality of the heating and air conditioning systems.

Do blower motor resistors get hot?

Higher wattage resistors get very hot when in use. This is because they are designed to be close to tolerance, in order to avoid burning up.

Does a relay click when it’s bad?

If your starter relay goes bad, the electrical signal will not make it from the battery to the starter motor. This will result in your engine not turning over – no matter how many times you turn the key.

Can Autozone test a relay?

A relay can be checked with a jump cable, a voltmeter, an ohmometer, or a test light. If the terminals are accessible and the relay is not controlled by a computer, the fastest method will be using a jump cable and test light.

How do you bypass a relay?

Why is my car not blowing any air?

The most common reasons why air doesn’t flow out of your car’s vents are because the intake is blocked or the ventilation system is not working properly.

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Why does the heat in my car only work when Im driving?

The most common cause of a car heater that only works when driving is a low coolant level. If the airlocked coolant system is also affected, it will not allow the engine to reach operating temperature.

How do you change a blower motor relay?

How to Change the Blower Motor Relay
  1. Locate your vehicle’s blower motor relay. …
  2. Open the glove box and empty its contents.
  3. Locate the two tabs on each side of the open glove box and push them in. …
  4. Remove the relay motor’s door panel by removing the two screws that hold it in place with a screwdriver.

Is there a fuse for the blower?

Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually located on or near the dashboard on the passenger side.

What fuse controls the heater fan?

The blower motor fuse is likely a 30 or 40 amp, and can be found on the fuse box cover or in the driver’s manual. To check for power at the blower motor fuse, use a test light or voltmeter.

How much does it cost to replace a relay switch?

The cost to replace a starter relay on a car can vary depending on the make and model of the car, but is typically in the range of $30 to $38. This price does not include tax or fees, and may not be accurate for your specific vehicle or location. In addition, other repairs may also be needed as a result of this repair.

What do relays do?

 motors, computers, etc.

Relays are used to open and close circuits by receiving electrical signals from outside sources. They can be found in a variety of places, including motors, computers, and other appliances.

Is it normal for a relay to get hot?

If you notice that the relay coil is hot during normal operation, it means that the service life of the relay has expired and should be replaced. If the contacts are also hot, this indicates an issue with those contacts and will lead to line failure (excessive voltage drop).

Why does my blower motor only work on low?

When a blower resistor fails, the fan speed that still works is usually the highest one. This is because it effectively bypasses the resistor and receives the maximum voltage.

Do all blower motors have a reset button?

If you need to reset your furnace, it is typically easy to do so. The reset button is typically located inside the blower housing near the blower motor.

Blower Motor Fan Relay Testing and Replacement


A blower motor relay is a vital component of your car’s cooling system. If it is not working properly, your car’s cooling system could be in trouble. Make sure to check your blower motor relay regularly to prevent problems.

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